PRINT RC4EncDecString$("abc", "g")
pause

FUNCTION RC4EncDecString(sData$, sKey$) AS STRING
	IF sData = "" || sKey = "" THEN FUNCTION = ""
	LOCAL aState[256] AS INTEGER
	LOCAL nKeyLength, nDataLength
	nKeyLength = LEN(sKey)
	nDataLength = LEN(sData)
	LOCAL sMid$, iIndex%, xCC%, yCC%, sResult$, sSwap, iMid
	FOR INTEGER iCC = 0 TO 255
		aState[iCC] = iCC
	NEXT

	FOR INTEGER iCC = 0 TO 255
		sMid = MID$(sKey, MOD(iCC, nKeyLength) + 1, 1)
		iIndex = MOD(ASC(sMid) + aState[iCC] + iIndex, 256)
		sSwap = aState[iCC]
		aState[iCC] = aState[iIndex]
		aState[iIndex] = sSwap
	NEXT
	
	FOR INTEGER iCC = 1 TO nDataLength
		xCC = MOD(xCC + 1, 256)
		yCC = MOD(aState[xCC] + yCC, 256)
		sSwap = aState[xCC]
		aState[xCC] = aState[yCC]
		aState[yCC] = sSwap
		iIndex = MOD(aState[xCC] + aState[yCC], 256)
		iMid = ASC(MID$(sData, iCC, 1)) XOR aState[iIndex]
		sResult = sResult & CHR$(iMid)
	NEXT
	FUNCTION = sResult
END FUNCTION